The mid-term future for fuel efficient vehicles with useful range is likely a hybrid solution of electric motors powered by batteries, topped up by a fuel-burning generator.

Dr. Norbert Müller at Michigan State, backed by $2.5 million from the US Government, aims to make that last part of the equation a much more compact and efficient proposition with a revolutionary new form of combustion engine.

The culmination of years of research, the latest version is in the form of a spinning metal disc with precisely-calculated radial channels. Fuel/air mixture enters via the central hub and travels outwards. As the disc spins the channel exit becomes closed off causing a back-shock. Because the inlet port is now closed off to the channel this causes compression (like a piston) and the fuel/air mixture is then ignited. The expansion of the explosion powers the wheel, opening the channel once more to the inlet and outlet ports. The exhaust gas is ejected and fuel/air is sucked in to repeat the process – at very high speed naturally.

This elegant design does away with many of the moving parts and circulatory systems of conventional combustion engines that lower their fuel-use efficiency, typically 15%. Dr. Müller is obtaining efficiencies of 60% with the wave disc design and of course the weight of the engine is greatly reduced.